Much of that is provided by Josh Brolin, in a spot-on imitation of Tommy Lee Jones as they share the role of Agent K at different ages, as Agent J (Will Smith) goes back to the future to alter circumstances that otherwise will lead to his alien-fighting partner's assassination. As he did the first two times, director Barry Sonnenfeld keeps the proceedings fast and fun. Emma Thompson co-stars. DVD extras: "making-of" documentary; outtakes; music video. *** (PG-13: AS, P, V) (Also on Blu-ray and Movies on Demand)